Preheat oven to 350 degrees. In medium saucepan combine onions with water to cover. Bring to boil; boil 1 minute. Drain well. Transfer to 8 inch or so baking dish coated with oil or butter. In bowl combine buttermilk or soya milk and cornstarch . Stir until cornstarch is completely dissolved and then mix in egg whites, salt and pepper. Pour over onions and sprinkle with cheese and paprika. Bake for 25 minutes. Serves 6.